Abstract 10322: Impact of Cryoablation on Esophageal Injury in a Canine Model
Introduction: Balloon cryoablation of pulmonary veins (PVs) has emerged as a promising technique for the isolation of potentially arrhythmogenic substrate. Whether cryoablation is likely to create atrio-esophageal(ESO) fistula formation remains unclear.
Purpose: In order to establish the occurrence, determinants and natural history of E injury, ablation was undertaken in 10 dogs using a 23 mm cryoballoon.
Methods: The right (RI) and left inferior(LI) PVs were targeted with 4 applications of cryothermy for 4 minutes each. ESO temperatures were monitored via a 20 mm circular luminal temperature probe positioned at the level of the cryoballoon. Injury was assessed endoscopically at pre-ablation, 1 week, 2–3 weeks, and until resolution. Pathological inspection was done upon necropsy.
Results: Cryo delivery time was 16 min per vein except for 1 RI PV (12 min). Right side mucosal ulcers were noted in 7/10 RI PVs while 2/10 LI PV cryoablation resulted in left anterior ulcers. Two dogs had bilateral mucosal ulcers. Ulcers measured 9.0 ± 5.1 by 8.0 ± 3.5 mm at peak. Maximum depth was 2 mm in 2/8 right anterior ulcers. ESO wall thickness at baseline and at 1–8 days post ablation was unchanged. Mean ESO to LI distances at baseline and 1–8 days were 2.6 ± 0.7 mm in those with vs 9.3 ± 4.4 mm (p<0.01) in those without ulcers. Mean ESO to RI distances were 2.0 ± 0.6 mm vs 5.8 ± 2.7 mm (p<0.01) with and without ulceration. All ulcers had healed by 42± 4 days with visible mucosal surface scarring but without visible scarring on the muscularis externa surface. No atrio-esophageal fistula was observed in any dog. Balloon and ESO luminal temperatures are as in Table. A luminal ESO temperature cutoff of 16°C had 86% PPV and 90% NPV in the development of ulcer.
Conclusions: Cryoablation of closely related PV can lead to consistent ESO mucosal ulcer formation as heralded by temperature changes during ablation. Nevertheless, these do not lead to AE fistula formation or full thickness ESO injury or scarring.
- © 2010 by American Heart Association, Inc.